/// <summary>
/// Appends truncated double sha256 checksum to a byte array
/// </summary>
/// <param name="data">byte array from bitcoin script representing an address</param>
/// <returns>byte array with appended checksum</returns>
private static byte[] AddCheckSum(byte[] data)
{
SHA256 sha256 = new SHA256Managed();
var hash1 = sha256.ComputeHash(data);
var hash2 = sha256.ComputeHash(hash1);
var checkSum = new byte[CheckSumBytes];
Buffer.BlockCopy(hash2, 0, checkSum, 0, checkSum.Length);
var dataWithCheckSum = ArrayTools.ConcatArrays(data, checkSum);
return(dataWithCheckSum);
}
/// <summary>
/// Encodes a bech32 address
/// </summary>
/// <param name="witnessVersion">the witness version (only v0 exists so far)</param>
/// <param name="witnessScriptData">byte array representing address from bitcoin OP_0 (segwit) script</param>
/// <param name="mainnet">generate mainnet address, otherwise testnet address</param>
/// <returns>bech32 encoded string with checksum and header</returns>
public static string EncodeWithHeaderAndChecksum(byte witnessVersion, byte[] witnessScriptData, bool mainnet = true)
{
// header is bc for mainnet, or tb for testnet
var header = mainnet ? "bc" : "tb";
// convert byte array from 8bits to 5
var base5 = ConvertBits(witnessScriptData, 8, 5, true);
// generate checksum from witnessVersion concat base5 array
var checksumBytes = CreateChecksum(header, ArrayTools.ConcatArrays(new[] { witnessVersion }, base5));
// append the checksum to the base5 array
var combined = base5.Concat(checksumBytes).ToArray();
// convert byte array to bech32 string
var encoded = BytesToBech32String(combined);
// return address format - Header+Separator(1)+WitnessVersion+EncodedData
return(header + "1" + Digits[witnessVersion] + encoded);
}
